Connecticut-based FuelCell Energy (FCE) has applied for a prospective pathway for California’s Low Carbon Fuel Standard (LCFS) for the production of hydrogen fuel produced from biogas derived from the mesophilic anaerobic digestion of wastewater sludge at a publicly owned treatment works (POTW).
The biogas is cleaned, then internally reformed in an integrated hydrogen energy system (Tri-Gen DFC) that produces hydrogen fuel for transportation; electric power for plant operations and export; as well as thermal energy for plant use. Once the internal energy demands of the pathway have been met, any energy not utilized for process is considered to be surplus to the system boundary and is credited to the FCE pathway.
The Tri-Gen DFC system is expected to generate 1,270 kilogram per day of hydrogen fuel which would be used as a transportation fuel; 2,250kW of electric power; and 2 million Btus of thermal energy. The electrical energy produced is the net electricity after subtracting the parasitic load of the Tri-Gen DFC system (705 kW).
The FCE pathway is dependent upon an allocation of 44% of the biogas yield; the rest of the biogas being sent to the CHP system (business as usual).
All of the thermal energy, and part of the electrical energy will be used to meet the energy demands of the process units constrained within the system boundary established for the FCE pathway. The hydrogen fuel produced will be distributed to the nearby hydrogen stations following the hub and spoke distribution model.
|Source: ARB. Click to enlarge.
FCE proposes that the carbon intensity (CI) of the hydrogen is -0.82 gCO2e/MJ. ARB Staff is recommending approval of the proposed process as a prospective pathway; i.e., no LCFS credits can be claimed until the company supplies more operational data, and ARB staff completes an updated lifecycle analysis.
The FCE Tri-Gen DFC system was until recently operational at the Orange County Sanitation District Plant #1 (120 mgd) (OCSD), and was producing hydrogen, electric power, as well as thermal energy in a test project to demonstrate the economic and technical viability of high temperature fuel cells employed at CHP units. The proposed pathway is based upon the three-year demonstration project at OCSD.